1. Field of the Invention
The present invention relates to a focus detection condition display device for use in a camera provided with a focus detection device which detects the focus condition of a photographic lens relative to an object within a focus detection area in accordance with the light from the object passing through the photographic lens.
2. Description of the Prior Art
In a video camera provided with an automatic focusing system (hereinafter to be referred to as an AF), when an object in a focus detection area has little difference in brightness between a light part and a dark part therein, i.e., when it lacks contrast, or when the object is dark, the focus detection becomes impracticable. Therefore, there is such a type in which the focus detection area is enabled to be enlarged according to the need, and the focus detection is practiced in normal cases with a narrow focus detection area normally at the center of the viewfinder, and when the focus detection becomes impossible or impracticable, the focus detection area is manually enlarged and therewith the focus detection is practiced again.
Even in a video camera provided with such variable focus detection areas as described above, there is such a type that will not give an alarming display to notify an operator of its impracticability of the focus detection. With such a video camera, the operator tended to continue his photographing work under the same condition even if the AF function was rendered inoperative, and therefore, it was known only after observing the reproduced picture that he had taken an out-of-focus picture.
Also, there is a video camera indicating its impracticability of the focus detection by an LED or the like provided in the vicinity of the side of the viewfinder. With such a camera, however, the operator during his camera work is liable to concentrate his attention upon the central portion of the viewfinder to watch the object through the viewfinder. Thus, it sometimes happened that the operator overlooked the lit LED at the side of the viewfinder and therefore made no change of the focus detection area to produce an out-of-focus picture.
Further, when an object being taken comes so close to a video camera as to exceed the limit of minimum object distance of the photographic lens of the video camera, camera work would be performed under the out-of-focus condition and the AF system becomes inoperative. Therefore, there is a video camera indicating such a condition by an LED or the like provided at the side of the viewfinder.
With such video cameras that are provided with LEDs for giving alarms in the event of the camera becoming inoperative of the focus detection or the object coming closer to the camera than its minimum object distance, the LEDs have had to be disposed in a limited space of the viewfinder to make the arrangement within the viewfinder complex, it is not easy to recognize an alarm because the operator has had to turn his eyes from the focus detection area at the center of the viewfinder to the alarming LED at the side thereof, and further, number of parts would be increased by installing such LEDs and the like in the viewfinder.